Improvement in manufacture of iron and steel



5 sheet-ssheet 1. O. W. SIEMENS.

v Manufacture of Iron and Steel.

No. 205,980. Patented July 16, 1878.

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.! IFII C. W. SIEMENS. Manufacture of Iron and Steel. No. 205,980.Patented July 16, 187-8;

INVENTOR ATTORNEY I ll-llllllllnvll-l'illll Ill Ll u b W n a m "n N r W.w E 1 f 00 u n 1 m M IIPI .l I m U f. M n x o L n W 1 i p 1:1 n |||..1WHHI B L NdE . WlTN ESSES 5Sheets-Sheet3 G. W. SIEMENS. Manufacture pfIron and Steel.

No. 205,980. Patented J uly16, 1878.

ATTORNEY zzMymzw 5 Sheets-Sheet 4.

G. W. SIEMENS. Manufacture of Iron and Steel.

No. 205,980. Patented July I6, 1878.

WITNESSES INVENTOR @W N. PEIERS. PHOTWLITHOGRAFHER, WASHINGTON. D C.

UNITED STATES PATENT OFFICE.

CHARLES \V. SIEMENS, OF WESTMINSTER, ENGLAND.

IMPROVEMENT lN MANUFACTURE OF IRON AND STEEL.

Specification forming part of Letters Patent No. 205,980, dated July 16,1378; applicati n fil d December 2, 1876.

To all whom it may concern:

Be it known that 1, CHARLES WILLIAM SIEMENS, of Westminster, in thecounty of Middlesex, England, have invented an Improved Process audApparatus for the Mannfacture of Iron and Steel; and I do hereby declarethat the following is a full, clear, and exact description thereof, thatwill enable others skilled in the art to which it appertains to make anduse the same, reference being had to the accompanying drawings, and tothe letters of reference marked 1311816011,W1ll0l1 form a part of thisspecification.

My invention relates to that class of processes for the manufacture ofiron and steel which are conducted in rotative furnaces; and the naturethereof consists in certain improvements upon the processes described inUnited States Letters Patent No. 159,712-t-hat is to say, in conductingthe process of producing wrought-iron direct from the ore in such amanner that the ore is crushed and mixed with such proportions of otherores or fluxin g materials as will give a fluid slag, to be formed at acomparatively low temperature, which slag isitapped off before awelding-heat is attained, in order that a second and welding cinder maybe formed within the rotator without the earthy matters so removed, toassist in balling up the metallic iron, substantially as hereindescribed.

The rotative regenerative furnace made use of in mauufacturin g iron andsteel according to my improved process is illustrated in theaccompanying drawings, in which- Figure 1 represents a longitudinalsection. Fig. 2 is a sectional plan. Fig. 3 represents, on the leftside, a half transverse section, and on the right side a half transversesection. Fig. 4 represents a sectional elevation. Fig. 5 is a transversesection.

In the drawings, A is the rotat-ive furnace, in shape cylindrical, withflat ends. It is mounted on rollers, and, instead of clutchgearing, eachfurnace may be driven by a small independent engine. The throat or neckof the furnace A is in communication with three fines, B and G C. Thelower openingB is for gas only, and the flue brings it direct from theproducers K K at the back. The two lateral parts 0 G communicate,respectively, with the regenerators D D. These regenerators are used forheating air only, and are built in stages, provided with cleaning-doorsE. The bricks are laid so as to form longitudinal channels, and atintervals stoppings F are carried across, as shown'in Fig. 5, so thatthe air and products of combustion going to and from the furnace passbackward and forward several times.

G is the regulatingvalve, by which air is admitted to the furnace, andcommunicates with regulators D D by means of the reversing-valve II. Theair flows in on one side of the flap H into one regcnerator, while theproducts of combustion coming from the furnace pass from the otherregeuerator to the other side of the flap H, and thence to the chimneyflue 1. Thus when one regenerator is heated sufficiently by the issuingproducts of combustion, and the other is cooled by the incoming air, areversal of the flaps H effects a change in the direction of thecurrents, and the heat accumulated is returned to the furnace.

The gasproduecrs K K are of any usual well-known construction, andtherefore need no description.

The gas produced rises from the producers K K continuously, and flowsout hot through the regulating slide-valve L, of which two are shown,one to each producer, into the gas-flue, along which it passes to therotative chamber A. Thus the gaseous or other fuel flows in continuallythrough the port 13, while the lateral ports 0 c servo alternately togive ingress to the hot air and egress to the products of combustion.

The rotative chamber A is constructed of wrought-iron plates, boundtogether by strips and an gle-iron, riveted on, and further secured bytwo rings of rails, (shown at M M,) which also serve to support thechamber on the rollers N N. The whole is placed on a carriage, 1, madeof cast and wrought iron, and resting on four wheels, running on a pairof rails. Thus the rotative chamber may be moved toward or away from theregcnerator-neck.

The rotary motion is shown as imparted by a small independent engine,13, provided with suitable gearing. There may be one such eugine to eachfurnace, and this arrangement may be used instead of the clutch-gearingdescribed in my previous patent. This engine may also be connected withthe carriage 1, and employed for moving the rotative chamber A to orfrom the regenerator-neck.

The neck of the furnace, opposite the door, is composed of twochannel-irons, or of iron plates bent U-shapcd. They are circularpieces, one fastened onto the back plate of the rotative chamber A, andthe other similarly secured to the neck-like extension of theregeneratorflucs, which also is made of wrought-iron plates, firmlyriveted together, and kept in position by the tuck-staves and tie-boltsIt.

Above the neck-joint a pertbrated pipe, S, sends aspray of water overthe plates and neck, to prevent their corrosion by the flame. The wateris prevented from entering the neck joint by the semicircular piece ofangle-iron S immediately below the perforated pipe S.

At T are shown the perforated tubes for projecting water upon the casingof A, in order to cool the furnacelining, and for other purposes.

The rotativc chamber A may be also cooled by making the casing hollow,and allowing water to circulate in the annular space.

This form of furnace, as above described, is well adapted for the use ofpetroleum or other oil-vapors, or for powdered fuel, as well as forordinary gaseous combustibles.

In making the lining of the rotativc cham ber, scale or other oxides ofiron, as also oxides of manganese, chromium, or titanium may be usedtogether or separatel y, or in combination with a rich cinder, such asthat obtained from reheating and puddlingfurnaces. A rich aluminouscinder is also very useful for admixture in certain cases.

In using an oxide lining I operate as follows: ()n the rotatorcasing,protected by brickwork or otherwise, an initial lining of oxide of ironis first melted and set around to the depth of a few inches. Then acharge of oxide and rich cinder, mixed, is melted and set around. (inthis bed an ordinary charge of oretiuxes, &c., is worked.

the usual manner. The heat is then raised, the balls are formed, and atthe same time a second cinder appears, derived partly from the balls andpartly from the lining. This should be a true wclding-cinder of theapproximate formula ZFeOSitb. After the balls are taken out this cinderis not tapped off, but is enriched by the addition of some of thebefore-mentioned oxides. Some of it is then splashed on the furnaceends, and the remainder is allowed to set, so as to form a newworking-face for the lining. In order to cool the furnace for thispurpose the admis- \\'hen the charge has come to the metallic conditionand the iron is partly aggregated, the fluid seoria is tapped off insion of air and gas is stopped or greatly diminished, and water isprojected on the easing in jets from perforated tubes placed above andbelow the outside of the rotative chamber.

If the lining is to be increased all around, the chamber is allowed torotate slowly while the cooling takes place; but if it be desirable toform a flat side to the lining, to prevent the sliding of subsequentcharges, the rotation is stopped, and, after enriching the cinder withscale or other oxides, lumps of titanium, or chromium, or of otherrefractory materials, such, for example, as rich calcined ironstone, orlumps of hematite, or magnetic iron ore, which, by preference, have beenpreviously warmed to avoid decomposition, are thrown into the bath andwell coated with cinder. The water is then turned onto the bottom of therotative chamber, and the flat is quickly solidified. The lumps set ingive a rough surface, and not only materially assistin preventing thecharge from sliding, but also help to keep it continually turning overand exposing fresh surface to the action of the flame. In this way eachcharge contributes to the lining for a subsequent one, and loss of ironis avoided.

A carbon or carbonaceous lining may be used with advantage, especiallyif iluid steel, spiegcl, ferrinuanganese, or spongy iron is to beformed. For such purposes I use graphite (plumbago) or the graphiticdeposit found in gas-retorts. Anthracite or coke may also be employed.These materials are to be ground up and mixed with about twenty-fivepercent. of fire-clay, so as to form a thick pasty mass, which is thenrammed into position or molded into suitable blocks for lining thefurnace.

Having now described the improvements in my rotative furnace and themode of forming the lining, I will proceed to explain my new method ofworking.

The ore-redueingagents and fluxes tobe used are first crushed smallenough to pass through holes about thrcc-eighths of an inch diameter.Then, if the ores contain volatile matter, they maybe calcined by anysuitable means previous to being charged into the rotator. The hot ore,after such preliminary treatment, is mixed with a suitable proportion ofreducing agents and fluxes.

In selecting the fluxes, my aim is to form a slag easily fusible, andcapable of carrying oil the sulphur, phosphorus, and earthy matters inthe charge at the first tapping, which takes place at a comparativelylow temperature, and just as the reduced iron begins to aggregate. Ifthe ore be silicated, bases, such as lime and alumina, should be added;or, if it be a basic ore, then silica must be added. In either case, theoxygen in the silica (as SiO should be at least about half thatcontained in the bases. If these conditions be assured only a smallquantity of iron will be carried oil in the sla If the ore contains muchsulphur and phosphorus and refractory earthy matter, I add an orecontaining manganese, so as to insure a fusible and cleansing slag atthe first tappin g.

The mixture of ore, flux, and reducingagents is charged into the heatedvolatile chamber, and rotation slowly commenced as soon as the charge isheated up thoroughly and the slag begins to run. The heat is thenslightly raised until the reduced spongy pieces of iron begin toaggregate in a bath of slag. This is now nearly all tapped off, and theheat is then raised to the welding-point of iron. At this stage some ofthe lining begins to melt, and a second small bath of cinder is formed,in which the balling-up goes on rapidly. As soon as ready, the balls arequickly removed and shingled straight into blooms and rolled intopuddled bars. This cinder, which is approximately a true welding-cinderof the composition 2Fe0,SiO is not tapped off, but is at once set aroundor in a flat, being evolved by the water from the perforated tubes belowthe rotator, and the furnace is ready for the next charge. From time totime the welding-cinder should be enriched and lumps set in, aspreviously described.

If hard-grained or steely iron be required, I add granulated pig-metal,refined metal, spiegel, or ferro-manganese to the charge immediatelyafter the first tapping. The carbon becomes associated with the iron inthe charge, while the silicon and manganese go into the cinder, to beset around as lining. 1n the charge which follows, the manganesesilicate comes out in the first tapping, and serves to cleanse thecharge from impurities.

The apparatus herein described forms the subject-matter of anotherapplication for Letters Patent, and is not herein claimed.

In the process for manufacturing iron and steel for which Letters Patentof the United States were granted to me February 9, 1875, the mixedmaterial was introduced into a slowlyrotating furnace and heated nearlyto the fusing'point of the ore, whereupon was added a quantity of thereducing agent, previously crushed, but not ground fine; or charcoal orwood, previously dried and cut into pieces. By the slow rotation of thefurnace the carbonaceous matter became covered by the heated ore, withwhich it was gradually mingled, while fresh intensely-heated surface wascontinually presented to the mixture. When the reaction was complete therotation of the furnace was stopped and the scoria tapped oft, so as toliberate the metallic iron resulting from the reaction. A fuller supplyof gaseous fuel was then turned on, and the furnace was caused to rotatefive or six times more rapidly than be fore, which had the effect ofagglomeratin g the iron into balls.

If it was desired to convert the balls into cast-steel, or into a purecast metal intermediate between cast-steel and cast-iron, after theballs were formed the rotation of the furnace was stopped and the fluidscoria again tapped off, whereupon the furnace was again caused torotate slowly. Some hard carbonaceous substance, such as crushedanthracite or coke, was then introduced, while the heat of the furnacewas raised to a high intensity. The balls, combining with the carbon,became fused into a fluid mass, which could be tapped or cast into formor molds; or, instead of introducing hard carbonaceous substances toeffeet the fusion of the balls, broken pig-metal, or spiegeleisen, orferro-manganese was employed for the same purpose.

Having thus described the nature of my invention and the manner in whichthe same is to be practically carried out, I claim The improvement inthe art of producing wrought-iron direct from the ore, hereinbeforedescribed, which consists in charging the crushed ore into the rotator,together with such proportions of other ores or fluxing material as willgive a fluid slag, tapping off the said slag before a welding-heat isattained, and reducing and balling the metallic iron in the presence ofa second and welding cinder formed within the rotator after the earthymatters have been removed, whereby the balling up of the metallic ironis aided, substantially as described.

U. WILLIAM SIEMENS.

Witnesses:

A. THoRPE Por'rs, EDWARD G. INGERSOLL.

